Method of forming a structure on a substrate

ABSTRACT

The invention relates to a method of providing a structure by depositing a layer on a substrate in a reactor. The method comprising:
         introducing a silicon halide precursor in the reactor;   introducing a reactant gas comprising oxygen in the reactor; and,   providing an energy source to create a plasma from the reactant gas so that the oxygen reacts with the first precursor in a layer comprising silicon dioxide.

FIELD OF INVENTION

The present disclosure generally relates to methods and systems formanufacturing electronic devices. More particularly, the disclosurerelates to methods for providing a structure by depositing a layer on asubstrate in a reactor.

BACKGROUND

As the trend has pushed structures in semiconductor devices to smallerand smaller sizes, different patterning techniques have arisen toproduce these structures. These techniques include spacer defined doubleor quadruple patterning, (immersion) lithography (193i), extremeultraviolet lithography (EUV), and directed self-assembly (DSA)lithography. Lithography may be combined with spacer defined double orquadruple patterning.

In these techniques it may be advantageous to transfer the pattern ofthe polymer resist to a hardmask. A hardmask is a material used insemiconductor processing as an etch mask with a good etching resistanceand etching selectivity to produce small structures. The hardmask may bemade from a silicon dioxide layer.

Spacers may also be used in semiconductor manufacturing to protectagainst subsequent processing steps and may be made from silicondioxide.

Further silicon dioxide can be used to fill gaps in the structures ofsemiconductor devices.

It is therefore advantageous to produce a silicon dioxide layer.

SUMMARY

In accordance with at least one embodiment of the invention there isprovided a method of providing a structure by depositing a layer on asubstrate in a reactor, the method comprising:

-   -   introducing a silicon halide precursor in the reactor;    -   introducing a reactant gas comprising oxygen in the reactor;        and,    -   providing an energy source to create a plasma from the reactant        gas so that the oxygen reacts with the first precursor in the        layer comprising silicon dioxide.

The reactant gas may comprise substantially no nitrogen. By using areactant gas which is substantially nitrogen free a silicon dioxidelayer may be deposited. The layer may have an improved etch rate. Withsubstantially no nitrogen a nitrogen concentration of less than 5000ppm, preferably less than 1000 ppm and most preferably less than 100 ppmnitrogen may be meant.

According to a further embodiment there is provided a method ofproviding a structure by depositing a layer on a substrate, the methodcomprising:

-   -   providing a silicon halide precursor in the reactor;    -   providing a reactant gas comprising oxygen in the reactor;    -   providing an energy source to create a plasma from the reactant        gas so that the reactant gas reacts with the silicon halide        precursor until the layer comprising silicon dioxide is formed.

For purposes of summarizing the invention and the advantages achievedover the prior art, certain objects and advantages of the invention havebeen described herein above. Of course, it is to be understood that notnecessarily all such objects or advantages may be achieved in accordancewith any particular embodiment of the invention. Thus, for example,those skilled in the art will recognize that the invention may beembodied or carried out in a manner that achieves or optimizes oneadvantage or group of advantages as taught or suggested herein withoutnecessarily achieving other objects or advantages as may be taught orsuggested herein.

All of these embodiments are intended to be within the scope of theinvention herein disclosed. These and other embodiments will becomereadily apparent to those skilled in the art from the following detaileddescription of certain embodiments having reference to the attachedfigures, the invention not being limited to any particular embodiment(s)disclosed.

BRIEF DESCRIPTION OF THE FIGURES

These and other features, aspects, and advantages of the inventiondisclosed herein are described below with reference to the drawings ofcertain embodiments, which are intended to illustrate and not to limitthe invention.

FIG. 1 is a flowchart in accordance with at least one embodiment of theinvention.

FIGS. 2a and 2b shows a PECVD SiO2 layer formed at 550° C. according toan embodiment before (2 a) and after (2 b) etching.

FIGS. 3a and 3b shows a PECVD SiO2 layer formed at 400° C. according toan embodiment before (3 a) and after (3 b) etching.

FIGS. 4a and 4b shows a PEALD SiO2 layer formed at 550° C. according toan embodiment before (4 a) and after (4 b) etching.

FIGS. 5a and 5b shows a PEALD SiO2 layer formed at 400° C. according toan embodiment before (5 a) and after (5 b) etching.

It will be appreciated that elements in the figures are illustrated forsimplicity and clarity and have not necessarily been drawn to scale tohelp improve understanding of illustrated embodiments of the presentdisclosure.

DETAILED DESCRIPTION

Although certain embodiments and examples are disclosed below, it willbe understood by those in the art that the invention extends beyond thespecifically disclosed embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Thus, it is intended thatthe scope of the invention disclosed should not be limited by theparticular disclosed embodiments described below.

The particular implementations shown and described are illustrative ofthe invention and its best mode and are not intended to otherwise limitthe scope of the aspects and implementations in any way. Indeed, for thesake of brevity, conventional manufacturing, connection, preparation,and other functional aspects of the system may not be described indetail.

Silicon dioxide films have a wide variety of applications, as will beapparent to the skilled artisan, such as in planar logic, DRAM, and NANDFlash devices. More specifically, conformal silicon dioxide thin filmsthat display uniform etch behavior have a wide variety of applications,both in the semiconductor industry and also outside of the semiconductorindustry. According to some embodiments of the present disclosure,various silicon dioxide films and precursors and methods for depositingthose films by atomic layer deposition (ALD) are provided. Importantly,in some embodiments the silicon dioxide films have a relatively uniformetch rate for both the vertical and the horizontal portions, whendeposited onto 3-dimensional structures. Such three-dimensionalstructures may include, for example and without limitation, FinFETS orother types of multiple gate FETs.

Thin film layers comprising silicon oxide can be deposited byplasma-enhanced atomic layer deposition (PEALD) or chemical vapordeposition (PECVD) type processes or by thermal ALD processes. In someembodiments a silicon oxide thin film is deposited over a threedimensional structure, such as a fin in the formation of a finFETdevice, and/or in the application of spacer defined double patterning(SDDP) and/or spacer defined quadruple patterning (SDQP). In someembodiments a silicon oxide thin film is deposited over a flat layer asa hard mask and subsequent layer are positioned on top for lithographicprocessing.

The formula of the silicon dioxide is generally referred to herein asSiO₂ for convenience and simplicity. However, the skilled artisan willunderstand that the Si:O ratio in the silicon dioxide layer andexcluding hydrogen or other impurities, can be represented as SiOx,where x varies from about 0.5 to about 2.0, as long as some Si—O bondsare formed. In some cases, x may vary from about 0.9 to about 1.7, fromabout 1.0 to about 1.5, or from about 1.2 to about 1.4. In someembodiments unstable silicon monoxide is formed which may decompose inSi and SiO₂.

ALD-type processes are based on controlled, generally self-limitingsurface reactions. Gas phase reactions are typically avoided bycontacting the substrate alternately and sequentially with thereactants. Vapor phase reactants are separated from each other in thereaction chamber, for example, by removing excess reactants and/orreactant byproducts between reactant pulses. The reactants may beremoved from proximity with the substrate surface with the aid of apurge gas and/or vacuum. In some embodiments excess reactants and/orreactant byproducts are removed from the reaction space by purging, forexample with an inert gas.

The methods presented herein provide for deposition of SiO₂ thin filmson substrate surfaces. Geometrically challenging applications are alsopossible due to the nature of ALD-type processes. According to someembodiments, ALD-type processes are used to form SiO₂ thin films onsubstrates such as integrated circuit workpieces, and in someembodiments on three-dimensional structures on the substrates. In someembodiments, ALD type processes comprise alternate and sequentialcontact of the substrate with a silicon halide precursor and an oxygenprecursor. In some embodiments, a silicon precursor contacts thesubstrate such silicon species adsorb onto the surface of the substrate.In some embodiments, the silicon species may be same as the siliconprecursor, or may be modified in the adsorbing step, such as by losingone or more ligands.

According to certain embodiments, a silicon dioxide thin film may beformed on a substrate by an ALD-type process comprising multiple silicondioxide deposition cycles, each silicon dioxide deposition cyclecomprising:

-   -   (1) contacting a substrate with a first silicon precursor,        preferably a silicon halide such that the silicon species adsorb        on the substrate surface;    -   (2) contacting the substrate with an oxygen comprising reactant        gas; and    -   (3) repeating steps (1) and (2) as many times as required or        desired to achieve a thin film of a desired thickness and        composition. Excess reactants may be removed from the vicinity        of the substrate, for example by purging from the reaction space        with an inert gas, after each contacting step.

PEALD Processes

In some embodiments, plasma enhanced ALD (PEALD) processes are used todeposit silicon dioxide films. Briefly, a substrate or workpiece isplaced in a reaction chamber and subjected to alternately repeatedsurface reactions. In some embodiments, thin silicon dioxide films areformed by repetition of a self-limiting ALD cycle. Preferably, forforming silicon dioxide films, each ALD cycle comprises at least twodistinct phases. The provision and removal of a reactant from thereaction space may be considered a phase. In a first phase, a firstreactant comprising silicon is provided and forms no more than about onemonolayer on the substrate surface. This reactant is also referred toherein as “the silicon precursor,” “silicon-containing precursor,” or“silicon reactant” and may be, for example, a silicon halide such asH₂SiI₂.

In a second phase, a (second) reactant comprising a reactive species isprovided and may convert adsorbed silicon species to silicon dioxide. Insome embodiments the reactant gas comprises an oxygen precursor. In someembodiments, the reactive species comprises an excited species. In someembodiments the reactant comprises a species from an oxygen containingplasma. In some embodiments, the reactant comprises oxygen radicals,oxygen atoms and/or oxygen plasma. In some embodiments, the reactant maycomprise O-containing plasma or a plasma comprising O. In someembodiments, the reactant may comprise a plasma comprising O-containingspecies. In some embodiments the reactant may comprise oxygen atomsand/or O* radicals. The reactant gas may comprise other species that arenot oxygen precursors. In some embodiments, the reactant may comprise aplasma of argon, radicals of argon, or atomic argon in one form oranother. In some embodiments, the reactant may comprise a species from anoble gas, such as He, Ne, Ar, Kr, or Xe, preferably Ar or He, forexample as radicals, in plasma form, or in elemental form. Thesereactive species from noble gases do not necessarily contribute materialto the deposited film, but can in some circumstances contribute to filmgrowth as well as help in the formation and ignition of plasma. In someembodiments a gas that is used to form a plasma may flow constantlythroughout the deposition process but only be activated intermittently.In some embodiments, the reactant does not comprise a species from anoble gas, such as Ar. Thus, in some embodiments the adsorbed siliconhalide precursor is not contacted with a reactive species generated by aplasma from Ar.

Additional phases may be added and phases may be removed as desired toadjust the composition of the final film.

One or more of the reactants may be provided with the aid of a carriergas, such as for example Ar or He. In some embodiments the siliconhalide precursor and the reactant are provided with the aid of a carriergas.

In some embodiments, two of the phases may overlap, or be combined. Forexample, the silicon halide precursor and the reactant may be providedsimultaneously in pulses that partially or completely overlap. Inaddition, although referred to as the first and second phases, and thefirst and second reactants, the order of the phases may be varied, andan ALD cycle may begin with any one of the phases. That is, unlessspecified otherwise, the precursors and reactants can be provided in anyorder, and the process may begin with any of the precursors or reactant.

As discussed in more detail below, in some embodiments for depositing asilicon dioxide film, one or more deposition cycles begin with provisionof the silicon halide precursor, followed by the reactant. In otherembodiments deposition may begin with provision of the reactant,followed by the silicon halide precursor.

In some embodiments the substrate on which deposition is desired, suchas a semiconductor workpiece, is loaded into a reactor. The reactor maybe part of a cluster tool in which a variety of different processes inthe formation of an integrated circuit are carried out. In someembodiments a flow-type reactor is utilized. In some embodiments ashower head type of reactor is utilized. In some embodiments, a spacedivided reactor is utilized. In some embodiments a high-volumemanufacturing-capable single wafer ALD reactor is used. In otherembodiments a batch reactor comprising multiple substrates is used. Forembodiments in which batch ALD reactors are used, the number ofsubstrates is preferably in the range of 10 to 200, more preferably inthe range of 50 to 150, and most preferably in the range of 100 to 130.

Exemplary single wafer reactors, designed specifically to enhance ALDprocesses, are commercially available from ASM America, Inc. (Phoenix,Ariz.) under the tradenames Pulsar® 2000 and Pulsar® 3000 and ASM JapanK.K (Tokyo, Japan) under the tradename Eagle® XP, XP8 and Dragon®.Exemplary batch ALD reactors, designed specifically to enhance ALDprocesses, are commercially available from and ASM Europe B.V (Almere,Netherlands) under the tradenames A400™ and A412™.

In some embodiments, if necessary, the exposed surfaces of the workpiececan be pretreated to provide reactive sites to react with the firstphase of the ALD process. In some embodiments a separate pretreatmentstep is not required. In some embodiments the substrate is pretreated toprovide a desired surface termination. In some embodiments the substrateis pretreated with plasma.

Excess reactant and reaction byproducts, if any, are removed from thevicinity of the substrate, and in particular from the substrate surface,between reactant pulses. In some embodiments the reaction chamber ispurged between reactant pulses, such as by purging with an inert gas.The flow rate and time of each reactant, is tunable, as is the removalstep, allowing for control of the quality and various properties of thefilms.

As mentioned above, in some embodiments a reaction gas is provided tothe reaction chamber continuously during each deposition cycle, orduring the entire ALD process, and reactive species are provided bygenerating a plasma in the reaction gas, either in the reaction chamberor upstream of the reaction chamber. In some embodiments the reactiongas comprises oxygen. In some embodiments the reaction gas is oxygen. Inother embodiments the reactant gas may comprise helium, or argon. Insome embodiments the reactant gas is helium or argon. The reactant gassuch as oxygen, argon, helium or argon may have a flow of 0.1 to 10,preferably 2 to 8, more preferably 3 to 6 and most preferably around 5slm. The gas may also serve as a purge gas for the precursor and/orreactant (or reactive species).

In some embodiments, nitrogen, argon, or helium may serve as a purge gasfor a first precursor and a source of excited species for converting thesilicon halide precursor to the silicon dioxide film.

The cycle is repeated until a film of the desired thickness andcomposition is obtained. In some embodiments the deposition parameters,such as the flow rate, flow time, purge time, and/or reactantsthemselves, may be varied in one or more deposition cycles during theALD process in order to obtain a film with the desired characteristics.In some embodiments, argon and/or argon plasma are not provided in adeposition cycle, or in the deposition process.

The term “pulse” may be understood to comprise feeding reactant into thereaction chamber for a predetermined amount of time. The term “pulse”does not restrict the length or duration of the pulse and a pulse can beany length of time.

In some embodiments, the silicon reactant is provided first. After aninitial surface termination, if necessary or desired, a first siliconreactant pulse is supplied to the workpiece. In accordance with someembodiments, the first reactant pulse comprises a carrier gas flow and avolatile silicon species, for example a silicon halide such as H₂SiI₂,that is reactive with the workpiece surfaces of interest. Accordingly,the silicon reactant adsorbs upon these workpiece surfaces. The firstreactant pulse self-saturates the workpiece surfaces such that anyexcess constituents of the first reactant pulse do not further reactwith the molecular layer formed by this process. The carrier gas mayhave a flow of 0.5 to 8, preferably 1 to 5, more preferably 2 to 3 andmost preferably around 2.8 slm.

The first silicon reactant pulse is preferably supplied in gaseous form.The silicon precursor gas is considered “volatile” for purposes of thepresent description if the species exhibits sufficient vapor pressureunder the process conditions to transport the species to the workpiecein sufficient concentration to saturate exposed surfaces.

In some embodiments the silicon reactant pulse is from about 0.05seconds to about 5.0 seconds, about 0.1 seconds to about 3 seconds orabout 0.2 seconds to about 1.0 seconds. The optimum pulsing time can bereadily determined by the skilled artisan based on the particularcircumstances.

In some embodiments the silicon reactant consumption rate is selected toprovide a desired dose of precursor to the reaction space. Reactantconsumption refers to the amount of reactant consumed from the reactantsource, such as a reactant source bottle, and can be determined byweighing the reactant source before and after a certain number ofdeposition cycles and dividing the mass difference by the number ofcycles. In some embodiments the silicon reactant consumption is morethan about 0.1 mg/cycle. In some embodiments the silicon reactantconsumption is about 0.1 mg/cycle to about 50 mg/cycle, about 0.5mg/cycle to about 30 mg/cycle or about 2 mg/cycle to about 20 mg/cycle.In some embodiments the minimum preferred silicon reactant consumptionmay be at least partly defined by the reactor dimensions, such as theheated surface area of the reactor. In some embodiments in a showerheadreactor designed for 300 mm silicon wafers, silicon reactant consumptionis more than about 0.5 mg/cycle, or more than about 2.0 mg/cycle. Insome embodiments the silicon reactant consumption is more than about 5mg/cycle in a showerhead reactor designed for 300 mm silicon wafers. Insome embodiments the silicon reactant consumption is more than about 1mg/cycle, preferably more than 5 mg/cycle at reaction temperatures belowabout 550° C. in a showerhead reactor designed for 300 mm siliconwafers.

After sufficient time for a molecular layer to adsorb on the substratesurface, excess first silicon reactant is then removed from the reactionspace. In some embodiments the excess first reactant is purged bystopping the flow of the first chemistry while continuing to flow acarrier gas or purge gas for a sufficient time to diffuse or purgeexcess reactants and reactant by-products, if any, from the reactionspace. In some embodiments the excess first precursor is purged with theaid of inert gas, such as argon, that is flowing throughout the ALDcycle.

In some embodiments, the first reactant is purged for about 0.1 secondsto about 10 seconds, about 0.3 seconds to about 5 seconds or about 0.3seconds to about 1 second. Provision and removal of the silicon reactantcan be considered the first or silicon phase of the ALD cycle.

In the second phase, a reactant comprising a reactive species, such asoxygen plasma is provided to the workpiece. Argon, Ar, is flowedcontinuously to the reaction chamber during each ALD cycle in someembodiments. Argon plasma may be formed by generating a plasma in argonin the reaction chamber or upstream of the reaction chamber, for exampleby flowing the argon through a remote plasma generator.

In some embodiments, plasma is generated upon flowing oxygen and argongases. In some embodiments the Ar and O₂ are provided to the reactionchamber before the plasma is ignited or oxygen and Ar ions or radicalsare formed. In some embodiments the Ar and O₂ are provided to thereaction chamber continuously and oxygen and Ar containing plasma, ionsor radicals is created or supplied when needed.

Typically, the reactant, for example comprising oxygen plasma, isprovided for about 0.1 seconds to about 10 seconds. In some embodimentsthe reactant, such as oxygen plasma, is provided for about 0.1 secondsto about 10 seconds, 0.5 seconds to about 5 seconds or 0.5 seconds toabout 2.0 seconds. However, depending on the reactor type, substratetype and its surface area, the reactant pulsing time may be even higherthan about 10 seconds. In some embodiments, pulsing times can be on theorder of minutes. The optimum pulsing time can be readily determined bythe skilled artisan based on the particular circumstances.

In some embodiments the reactant is provided in two or more distinctpulses, without introducing another reactant in between any of the twoor more pulses. For example, in some embodiments an oxygen plasma isprovided in two or more, preferably in two, sequential pulses, withoutintroducing a Si-precursor in between the sequential pulses. In someembodiments during provision of oxygen plasma two or more sequentialplasma pulses are generated by providing a plasma discharge for a firstperiod of time, extinguishing the plasma discharge for a second periodof time, for example from about 0.1 seconds to about 10 seconds, fromabout 0.5 seconds to about 5 seconds or about 1.0 seconds to about 4.0seconds, and exciting it again for a third period of time beforeintroduction of another precursor or a removal step, such as before theSi-precursor or a purge step. Additional pulses of plasma can beintroduced in the same way. In some embodiments a plasma is ignited foran equivalent period of time in each of the pulses.

Oxygen plasma may be generated by applying RF power of from about 10 Wto about 2000 W, preferably from about 50 W to about 1000 W, morepreferably from about 100 W to about 600 W in some embodiments. In someembodiments the RF power density may be from about 0.02 W/cm² to about2.0 W/cm², preferably from about 0.05 W/cm² to about 1.5 W/cm². The RFpower may be applied to oxygen that flows during the oxygen plasma pulsetime, that flows continuously through the reaction chamber, and/or thatflows through a remote plasma generator. Thus in some embodiments theplasma is generated in situ, while in other embodiments the plasma isgenerated remotely. In some embodiments a showerhead reactor is utilizedand plasma is generated between a substrate holder (on top of which thesubstrate is located) and a showerhead plate. In some embodiments thegap between the substrate holder and showerhead plate is from about 0.1cm to about 20 cm, from about 0.5 cm to about 5 cm, or from about 0.8 cmto about 3.0 cm.

After a time period sufficient to completely saturate and react thepreviously adsorbed molecular layer with the oxygen plasma pulse, anyexcess reactant and reaction byproducts are removed from the reactionspace. As with the removal of the first reactant, this step may comprisestopping the generation of reactive species and continuing to flow theinert gas, such as helium or argon for a time period sufficient forexcess reactive species and volatile reaction by-products to diffuse outof and be purged from the reaction space. In other embodiments aseparate purge gas may be used. The purge may, in some embodiments, befrom about 0.1 seconds to about 10 seconds, about 0.1 seconds to about 4seconds or about 0.1 seconds to about 0.5 seconds. Together, the oxygenplasma provision and removal represent a second, reactive species phasein a silicon dioxide atomic layer deposition cycle.

The two phases together represent one ALD cycle, which is repeated toform silicon dioxide thin films of a desired thickness. While the ALDcycle is generally referred to herein as beginning with the siliconphase, it is contemplated that in other embodiments the cycle may beginwith the reactive species phase. One of skill in the art will recognizethat the first precursor phase generally reacts with the terminationleft by the last phase in the previous cycle. Thus, while no reactantmay be previously adsorbed on the substrate surface or present in thereaction space if the reactive species phase is the first phase in thefirst ALD cycle, in subsequent cycles the reactive species phase willeffectively follow the silicon phase. In some embodiments one or moredifferent ALD cycles are provided in the deposition process.

According to some embodiments of the present disclosure, PEALD reactionsmay be performed at temperatures ranging from about 25° C. to about 700°C., preferably from about 50° C. to about 600° C., more preferably fromabout 100° C. to about 450° C., and most preferably from about 200° C.to about 400° C. In some embodiments, the optimum reactor temperaturemay be limited by the maximum allowed thermal budget. Therefore, in someembodiments the reaction temperature is from about 300° C. to about 400°C. In some applications, the maximum temperature is around about 400°C., and, therefore the PEALD process is run at that reactiontemperature.

According to some embodiments of the present disclosure, the pressure ofthe reaction chamber during processing is maintained between 0.08 to 40Torr, preferably 0.8 to 30 Torr and more preferably between 2 to 20Torr, and most preferably around 8 Torr.

PECVD Process

Plasma-enhanced chemical vapor deposition (PECVD) is a process used todeposit thin films from a gas state (vapor) to a solid state on asubstrate. Chemical reactions are involved in the process, which occurafter creation of a plasma of the reactive gases. The plasma iscontinuously applied to the space between which is filled with thereactive gases. In some embodiments, a radio frequency (RF) plasmasource is employed to create the plasma, though any type of plasmasource capable of generating a direct plasma may be employed, includingmicrowave and DC sources. Further, in some embodiments, aremotely-generated plasma may be employed to supply reactive species. Infurther embodiments (pulse PECVD) only one of the reactants, either theSilicon precursor or the reactive species is provided continuously tothe chamber while the other reactant is pulsed intermittently

Si Precursors

A number of suitable silicon halide precursors can be used in thepresently disclosed PEALD processes. At least some of the suitableprecursors may have the following general formula:

H_(2n+2−y−z)Si_(n)X_(y)A_(z)  (1)

wherein, n=1-10, y=1 or more (and up to 2n+2−z), z=0 or more (and up to2n+2−y), X is I or Br, and A is a halogen other than X, preferably n=1-5and more preferably n=1-3 and most preferably 1-2.

According to some embodiments, silicon halide precursors may compriseone or more cyclic compounds. Such precursors may have the followinggeneral formula:

H_(2n+2−y−z)Si_(n)X_(y)A_(z)  (2)

wherein the formula (2) compound is cyclic compound, n=3-10, y=1 or more(and up to 2n−z), z=0 or more (and up to 2n−y), X is I or Br, and A is ahalogen other than X, preferably n=3-6.

According to some embodiments, silicon halide precursors may compriseone or more iodosilanes. Such precursors may have the following generalformula:

H_(2n+2−y−z)Si_(n)I_(y)A_(z)  (3)

wherein, n=1-10, y=1 or more (and up to 2n+2−z), z=0 or more (and up to2n+2−y), and A is a halogen other than I, preferably n=1-5 and morepreferably n=1-3 and most preferably 1-2.

According to some embodiments, some silicon halide precursors maycomprise one or more cyclic iodosilanes. Such precursors may have thefollowing general formula:

H_(2n+2−y−z)Si_(n)I_(y)A_(z)  (4)

wherein the formula (4) compound is a cyclic compound, n=3-10, y=1 ormore (and up to 2n−z), z=0 or more (and up to 2n−y), and A is a halogenother than I, preferably n=3-6.

According to some embodiments, some silicon halide precursors maycomprise one or more bromosilanes. Such precursors may have thefollowing general formula:

H_(2n+2−y−z)Si_(n)Br_(y)A_(z)  (5)

wherein, n=1-10, y=1 or more (and up to 2n+2−z), z=0 or more (and up to2n+2−y), and A is a halogen other than Br, preferably n=1-5 and morepreferably n=1-3 and most preferably 1-2.

According to some embodiments, some silicon halide precursors maycomprise one or more cyclic bromosilanes. Such precursors may have thefollowing general formula:

H_(2n+2−y−z)Si_(n)Br_(y)A_(z)  (6)

wherein the formula (6) compound is a cyclic compound, n=3-10, y=1 ormore (and up to 2n−z), z=0 or more (and up to 2n−y), and A is a halogenother than Br, preferably n=3-6.

According to some embodiments, preferred silicon precursors comprise oneor more iodosilanes. Such precursors may have the following generalformula:

H_(2n+2−y−z)Si_(n)I_(y)  (7)

wherein, n=1-5, y=1 or more (up to 2n+2), preferably n=1-3 and morepreferably n=1-2.

According to some embodiments, preferred silicon halide precursorscomprise one or more bromosilanes. Such precursors may have thefollowing general formula:

H_(2n+2−y−z)Si_(n)I_(y)  (8)

wherein, n=1-5, y=1 or more (up to 2n+2), preferably n=1-3 and morepreferably n=1-2.

According to some embodiments of a PEALD process, suitable siliconhalide precursors can include at least compounds having any one of thegeneral formulas (1) through (8). In general formulas (1) through (8),halides/halogens can include F, Cl, Br and I. In some embodiments, asilicon halide precursor comprises SiI₄, HSiI₃, H₂SiI₂, H₃SiI, Si₂I₆,HSi₂I₅, H₂Si₂I₄, H₃Si₂I₃, H₄Si₂I₂, H₅Si₂I, or Si₃I₈. In someembodiments, a silicon halide precursor comprises one of HSiI₃, H₂SiI₂,H₃SiI, H₂Si₂I₄, H₄Si₂I₂, and H₅Si₂I. In some embodiments the siliconhalide precursor comprises two, three, four, five or six of HSiI₃,H₂SiI₂, H₃SiI, H₂Si₂I₄, H₄Si₂I₂, and H₅Si₂I, including any combinationsthereof.

In certain embodiments, the Si halide precursor is H₂SiI₂. In someembodiments, Si halide precursors of formulas (9)-(28), below, can beused in PEALD processes.

O-Precursors

As discussed above, the reactant according to the present disclosure maycomprise an oxygen precursor. In some embodiments the reactant in aPEALD process may comprise a reactive species. Suitable plasmacompositions include oxygen plasma, radicals of oxygen, or atomic oxygenin one form or another. In some embodiments, the reactive species maycomprise O-containing plasma or a plasma comprising O. In someembodiments, the reactive species may comprise a plasma comprisingO-containing species. In some embodiments the reactive species maycomprise oxygen atoms and/or O* radicals. In some embodiments, argonplasma, radicals of argon, or atomic argon in one form or another arealso provided. And in some embodiments, a plasma may also contain noblegases, such as He, Ne, Ar, Kr and Xe, preferably Ar or He, in plasmaform, as radicals, or in atomic form. In some embodiments, the reactantdoes not comprise any species from a noble gas, such as Ar. Thus, insome embodiments plasma is not generated in a gas comprising a noblegas.

In some embodiments the reactant may be formed, at least in part, fromO₂ and H₂, where the O₂ and H₂ are provided at a flow ratio (O₂/H₂) fromabout 20:1 to about 1:20, preferably from about 10:1 to about 1:10, morepreferably from about 5:1 to about 1:5 more preferably from about 1:2 toabout 4:1, and most preferably 1:1.

The reactant may be formed in some embodiments remotely via plasmadischarge (“remote plasma”) away from the substrate or reaction space.In some embodiments, the reactant may be formed in the vicinity of thesubstrate or directly above substrate (“direct plasma).

FIG. 1 is a flow chart generally illustrating a depositing a layer on asubstrate in a reactor in accordance with some embodiments. According tocertain embodiment, the process may comprise the following:

-   -   (1) a substrate comprising a three-dimensional structure is        provided in a reaction space;    -   (2) a silicon-containing precursor, such as SiI2H2, is        introduced into the reaction space so that silicon-containing        species are adsorbed to a surface of the substrate;    -   (3) excess silicon-containing precursor and reaction byproducts        may be substantially removed from the reaction space;    -   (4) an oxygen comprising reactant, such as O₂, H₂O, H₂O₂, is        introduced into the reaction chamber, and reactive species from        the oxygen are created and the reactive species are contacted        with the substrate; and    -   (5) removing excess oxygen atoms, plasma, or radicals and        reaction byproducts;    -   Steps (2) through (5) of the silicon dioxide deposition        cycle (7) may be repeated (6) until a silicon dioxide film of a        desired thickness is formed. The temperature of the substrate        may be between 25 to 700° C., preferably between 100 and 650°        C., more preferably between 200 and 625° C., most preferably        between 300 and 600° C. and even more preferable around 400° C.        during providing a reactant gas and providing an energy source        to create the plasma.

Oxygen may flow continuously throughout the silicon dioxide depositioncycle, with oxygen plasma formed at the appropriate times to convertadsorbed silicon compound into silicon dioxide.

As mentioned above, in some embodiments the substrate may be contactedsimultaneously with the silicon compound and the reactive oxygen speciesto form the layer in a plasma enhanced chemical vapor deposition (PECVD)process.

According to some embodiments, the silicon dioxide layer is depositedusing a plasma enhanced chemical vapor deposition (PEALD) process on asubstrate having three-dimensional features, such as in a FinFETapplication. The features may have an aspect ratios of more than 2,preferably an aspect ratios of more than 3, more preferably an aspectratios of more than 6 and most preferably an aspect ratios of more than11. The process may comprise the steps as described above in conjunctionwith FIG. 1.

Si Precursors

A number of suitable silicon halide precursors may be used in thepresently disclosed processes. In some embodiments these precursors maybe used in plasma ALD or plasma CVD processes thereby a layer with adesired quality (at least one of the desired WER, WERR, pattern loadingeffect or/and step coverage features described below) is deposited.

According to some embodiments, some silicon precursors comprise iodineor bromine and the film deposited by using that precursor has at leastone desired property, for example at least one of the desired WER, WERR,pattern loading effect or/and step coverage features described below.

At least some of the suitable precursors may have the following generalformula:

H_(2n+2−y−z−w)Si_(n)X_(y)A_(z)R_(w)  (9)

wherein, n=1-10, y=1 or more (and up to 2n+2−z−w), z=0 or more (and upto 2n+2−y−w), w=0 or more (and up to 2n+2−y−z), X is I or Br, A is ahalogen other than X, R is an organic ligand and can be independentlyselected from the group consisting of alkoxides, alkylsilyls, alkyl,substituted alkyl, alkylamines and unsaturated hydrocarbon; preferablyn=1-5 and more preferably n=1-3 and most preferably 1-2. Preferably R isa C₁-C₃ alkyl ligand, such as methyl, ethyl, n-propyl or isopropyl.

According to some embodiments, some silicon halide precursors compriseone or more cyclic compounds. Such precursors may have the followinggeneral formula:

H_(2n+2−y−z−w)Si_(n)I_(y)A_(z)R_(w)  (10)

wherein, n=3-10, y=1 or more (and up to 2n−z−w), z=0 or more (and up to2n−y−w), w=0 or more (and up to 2n−y−z), X is I or Br, A is a halogenother than X, R is an organic ligand and can be independently selectedfrom the group consisting of alkoxides, alkylsilyls, alkyl, substitutedalkyl, alkylamines and unsaturated hydrocarbon; preferably n=3-6.Preferably R is a C₁-C₃ alkyl ligand, such as methyl, ethyl, n-propyl orisopropyl.

According to some embodiments, some silicon halide precursors compriseone or more iodosilanes. Such precursors may have the following generalformula:

H_(2n-y-z-w)Si_(n)I_(y)A_(z)R_(w)  (11)

wherein, n=1-10, y=1 or more (and up to 2n+2−z−w), z=0 or more (and upto 2n+2−y−w), w=0 or more (and up to 2n+2−y−z), A is a halogen otherthan I, R is an organic ligand and can be independently selected fromthe group consisting of alkoxides, alkylsilyls, alkyl, substitutedalkyl, alkylamines and unsaturated hydrocarbon; preferably n=1-5 andmore preferably n=1-3 and most preferably 1-2. Preferably R is a C₁-C₃alkyl ligand, such as methyl, ethyl, n-propyl or isopropyl.

According to some embodiments, some silicon halide precursors compriseone or more cyclic iodosilanes. Such precursors may have the followinggeneral formula:

H_(2n+2−y−z−w)Si_(n)I_(y)A_(z)R_(w)  (12)

wherein, n=3-10, y=1 or more (and up to 2n−z−w), z=0 or more (and up to2n−y−w), w=0 or more (and up to 2n−y−z), A is a halogen other than I, Ris an organic ligand and can be independently selected from the groupconsisting of alkoxides, alkylsilyls, alkyl, substituted alkyl,alkylamines and unsaturated hydrocarbon; preferably n=3-6. Preferably Ris a C₁-C₃ alkyl ligand, such as methyl, ethyl, n-propyl or isopropyl.

According to some embodiments, some silicon halide precursors compriseone or more bromosilanes. Such precursors may have the following generalformula:

H_(2n+2−y−z−w)Si_(n)Br_(y)A_(z)R_(w)  (13)

wherein, n=1-10, y=1 or more (and up to 2n+2−z−w), z=0 or more (and upto 2n+2−y−w), w=0 or more (and up to 2n+2−y−z), A is a halogen otherthan Br, R is an organic ligand and can be independently selected fromthe group consisting of alkoxides, alkylsilyls, alkyl, substitutedalkyl, alkylamines and unsaturated hydrocarbon; preferably n=1-5 andmore preferably n=1-3 and most preferably 1-2. Preferably R is a C₁-C₃alkyl ligand, such as methyl, ethyl, n-propyl or isopropyl.

According to some embodiments, some silicon halide precursors compriseone or more cyclic bromosilanes. Such precursors may have the followinggeneral formula:

H_(2n-y-z-w)Si_(n)Br_(y)A_(z)R_(w)  (14)

wherein, n=3-10, y=1 or more (and up to 2n−z−w), z=0 or more (and up to2n−y−w), w=0 or more (and up to 2n−y−z), A is a halogen other than Br, Ris an organic ligand and can be independently selected from the groupconsisting of alkoxides, alkylsilyls, alkyl, substituted alkyl,alkylamines and unsaturated hydrocarbon; preferably n=3-6. Preferably Ris a C₁-C₃ alkyl ligand such as methyl, ethyl, n-propyl or isopropyl.

According to some embodiments, some silicon halide precursors compriseone or more iodosilanes or bromosilanes in which the iodine or bromineis not bonded to the silicon in the compound. Accordingly some suitablecompounds may have iodine/bromine substituted alkyl groups. Suchprecursors may have the following general formula:

H_(2n+2−y−z−w)Si_(n)X_(y)A_(z)R^(II) _(w)  (15)

wherein, n=1-10, y=0 or more (and up to 2n+2−z−w), z=0 or more (and upto 2n+2−y−w), w=1 or more (and up to 2n+2−y−z), X is I or Br, A is ahalogen other than X, R^(II) is an organic ligand containing I or Br andcan be independently selected from the group consisting of I or Brsubstituted alkoxides, alkylsilyls, alkyls, alkylamines and unsaturatedhydrocarbons; preferably n=1-5 and more preferably n=1-3 and mostpreferably 1-2. Preferably R^(II) is an iodine substituted C₁-C₃ alkylligand.

According to some embodiments, some silicon halide precursors compriseone or more cyclic iodosilanes or bromosilanes. Accordingly somesuitable cyclic compounds may have iodine/bromine substituted alkylgroups. Such precursors may have the following general formula:

H_(2n-y-z-w)Si_(n)X_(y)A_(z)R^(II) _(w)  (16)

wherein, n=3-10, y=0 or more (and up to 2n+2−z−w), z=0 or more (and upto 2n+2−y−w), w=1 or more (and up to 2n+2−y−z), X is I or Br, A is ahalogen other than X, R^(II) is an organic ligand containing I or Br andcan be independently selected from the group consisting of I or Brsubstituted alkoxides, alkylsilyls, alkyls, alkylamines and unsaturatedhydrocarbons; preferably n=3-6. Preferably R is an iodine substitutedC₁-C₃ alkyl ligand.

According to some embodiments, some suitable silicon halide precursorsmay have at least one of the following general formulas:

H_(2n+2−y−z−w)Si_(n)X_(y)A_(z)(NR₁R₂)_(w)  (17)

wherein, n=1-10, y=1 or more (and up to 2n+2−z−w), z=0 or more (and upto 2n+2−y−w), w=1 or more (and up to 2n+2−y−z), X is I or Br, A is ahalogen other than X, N is nitrogen, and R₁ and R₂ can be independentlyselected from the group consisting of hydrogen, alkyl, substitutedalkyl, silyl, alkylsilyl and unsaturated hydrocarbon; preferably n=1-5and more preferably n=1-3 and most preferably 1-2. Preferably R₁ and R₂are hydrogen or C₁-C₄ alkyl groups, such as methyl, ethyl, n-propyl,isopropyl, t-butyl, isobutyl, sec-butyl and n-butyl. More preferably R₁and R₂ are hydrogen or C₁-C₃ alkyl groups, such as methyl, ethyl,n-propyl or isopropyl. Each of the (NR₁R₂)_(w) ligands can beindependently selected from each other.

(H_(3-y-z-w)X_(y)A_(z)(NR₁R₂)_(w)Si)₃—N  (18)

wherein, y=1 or more (and up to 3−z−w), z=0 or more (and up to 3−y−w),w=1 or more (and up to 3−y−z), X is I or Br, A is a halogen other thanX, N is nitrogen and R₁ and R₂ can be independently selected from thegroup consisting of hydrogen, alkyl, substituted alkyl, silyl,alkylsilyl, and unsaturated hydrocarbon. Preferably R₁ and R₂ arehydrogen or C₁-C₄ alkyl groups, such as methyl, ethyl, n-propyl,isopropyl, t-butyl, isobutyl, sec-butyl and n-butyl. More preferably R₁and R₂ are hydrogen or C₁-C₃ alkyl groups, such as methyl, ethyl,n-propyl or isopropyl. Each of the (NR₁R₂), ligands can be independentlyselected from each other. Each of the threeH_(3-y-z-w)X_(y)A_(z)(NR₁R₂)_(w) Si ligands can be independentlyselected from each other.

In some embodiments, some suitable silicon halide precursors may have atleast one of the following more specific formulas:

H_(2n+2−y−w)Si_(n)I_(y)(NR₁R₂)_(w)  (19)

wherein, n=1-10, y=1 or more (and up to 2n+2−w), w=1 or more (and up to2n+2−y), N is nitrogen, and R₁ and R₂ can be independently selected fromthe group consisting of hydrogen, alkyl, substituted alkyl, silyl,alkylsilyl, and unsaturated hydrocarbon; preferably n=1-5 and morepreferably n=1-3 and most preferably 1-2. Preferably R₁ and R₂ arehydrogen or C₁-C₄ alkyl groups, such as methyl, ethyl, n-propyl,isopropyl, t-butyl, isobutyl, sec-butyl and n-butyl. More preferably R₁and R₂ are hydrogen or C₁-C₃ alkyl groups, such as methyl, ethyl,n-propyl or isopropyl. Each of the (NR₁R₂)_(w) ligands can beindependently selected from each other.

(H_(3-y-w)I_(y)(NR₁R₂)_(w)Si)₃—N  (20)

wherein, y=1 or more (and up to 3−w), w=1 or more (and up to 3−y), N isnitrogen and R₁ and R₂ can be independently selected from the groupconsisting of hydrogen, alkyl, substituted alkyl, silyl, alkylsilyl, andunsaturated hydrocarbon. Preferably R₁ and R₂ are hydrogen or C₁-C₄alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, t-butyl,isobutyl, sec-butyl and n-butyl. More preferably R₁ and R₂ are hydrogenor C₁-C₃ alkyl groups, such as methyl, ethyl, n-propyl or isopropyl.Each of the three H_(3-y-w)I_(y)(NR₁R₂)_(w)Si ligands can beindependently selected from each other.

According to some embodiments, some suitable silicon halide precursorsmay have at least one of the following general formulas:

H_(2n+2−y−z−w)Si_(n)X_(y)A_(z)(NR₁R₂)_(w)  (21)

wherein, n=1-10, y=1 or more (and up to 2n+2-z-w), z=0 or more (and upto 2n+2−y−w), w=1 or more (and up to 2n+2−y−z), X is I or Br, A is ahalogen other than X, N is nitrogen, R₁ can be independently selectedfrom the group consisting of hydrogen, alkyl, substituted alkyl, silyl,alkylsilyl, and unsaturated hydrocarbon, and R₂ can be independentlyselected from the group consisting of alkyl, substituted alkyl, silyl,alkylsilyl and unsaturated hydrocarbon; preferably n=1-5 and morepreferably n=1-3 and most preferably 1-2. Preferably R₁ is hydrogen orC₁-C₄ alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, t-butyl,isobutyl, sec-butyl, and n-butyl. More preferably R₁ is hydrogen orC₁-C₃ alkyl groups, such as methyl, ethyl, n-propyl, or isopropyl.Preferably R₂ is C₁-C₄ alkyl groups, such as methyl, ethyl, n-propyl,isopropyl, t-butyl, isobutyl, sec-butyl, and n-butyl. More preferably R₂is C₁-C₃ alkyl groups, such as methyl, ethyl, n-propyl, or isopropyl.Each of the (NR₁R₂)_(w) ligands can be independently selected from eachother.

(H_(3-y-z-w)X_(y)A_(z)(NR₁R₂)_(w)Si)₃—N  (22)

wherein, y=1 or more (and up to 3−z−w), z=0 or more (and up to 3−y−w),w=1 or more (and up to 3−y−z), X is I or Br, A is a halogen other thanX, N is nitrogen, R₁ can be independently selected from the groupconsisting of hydrogen, alkyl, substituted alkyl, silyl, alkylsilyl, andunsaturated hydrocarbon, and R₂ can be independently selected from thegroup consisting of alkyl, substituted alkyl, silyl, alkylsilyl, andunsaturated hydrocarbon; preferably n=1-5 and more preferably n=1-3 andmost preferably 1-2. Preferably R₁ is hydrogen or C₁-C₄ alkyl groups,such as methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl,sec-butyl, and n-butyl. More preferably R₁ is hydrogen or C₁-C₃ alkylgroups, such as methyl, ethyl, n-propyl, or isopropyl. Preferably R₂ isC₁-C₄ alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, t-butyl,isobutyl, sec-butyl, and n-butyl. More preferably R₂ is C₁-C₃ alkylgroups, such as methyl, ethyl, n-propyl, or isopropyl. Each of the(NR₁R₂) ligands can be independently selected from each other.

In some embodiments, some suitable silicon halide precursors may have atleast one of the following more specific formulas:

H_(2n+2−y−w)Si_(n)I_(y)(NR₁R₂)_(w)  (23)

wherein, n=1-10, y=1 or more (and up to 2n+2−w), w=1 or more (and up to2n+2−y), N is nitrogen, R₁ can be independently selected from the groupconsisting of hydrogen, alkyl, substituted alkyl, silyl, alkylsilyl, andunsaturated hydrocarbon, and R₂ can be independently selected from thegroup consisting of alkyl, substituted alkyl, silyl, alkylsilyl, andunsaturated hydrocarbon; preferably n=1-5 and more preferably n=1-3 andmost preferably 1-2. Preferably R₁ is hydrogen or C₁-C₄ alkyl groups,such as methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl,sec-butyl, and n-butyl. More preferably R₁ is hydrogen or C₁-C₃ alkylgroups, such as methyl, ethyl, n-propyl, or isopropyl. Preferably R₂ isC₁-C₄ alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, t-butyl,isobutyl, sec-butyl, and n-butyl. More preferably R₂ is C₁-C₃ alkylgroups, such as methyl, ethyl, n-propyl, or isopropyl. Each of the(NR₁R₂)_(w) ligands can be independently selected from each other.

(H_(3-y-w)I_(y)(NR₁R₂)_(w)Si)₃—N  (24)

wherein, y=1 or more (and up to 3−w), w=1 or more (and up to 3−y), N isnitrogen, R₁ can be independently selected from the group consisting ofhydrogen, alkyl, substituted alkyl, silyl, alkylsilyl, and unsaturatedhydrocarbon, and R₂ can be independently selected from the groupconsisting of alkyl, substituted alkyl, silyl, alkylsilyl, andunsaturated hydrocarbon; preferably n=1-5 and more preferably n=1-3 andmost preferably 1-2. Preferably R₁ is hydrogen or C₁-C₄ alkyl groups,such as methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl,sec-butyl, and n-butyl. More preferably R₁ is hydrogen or C₁-C₃ alkylgroups, such as methyl, ethyl, n-propyl, or isopropyl. Preferably R₂ isC₁-C₄ alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, t-butyl,isobutyl, sec-butyl, and n-butyl. More preferably R₂ is C₁-C₃ alkylgroups, such as methyl, ethyl, n-propyl, or isopropyl. Each of the(NR₁R₂)_(w) ligands can be independently selected from each other.

According to some embodiments of a thermal ALD process, suitable siliconhalide precursors can include at least compounds having any one of thegeneral formulas (9) through (24). In general formulas (9) through (18)as well as in general formulas (21) and (22), halides/halogens caninclude F, Cl, Br and I.

In some embodiments, a silicon halide precursor comprises one or more ofthe following: SiI₄, HSiI₃, H₂SiI₂, H₃SiI, Si₂I₆, HSi₂I₅, H₂Si₂I₄,H₃Si₂I₃, H₄Si₂I₂, H₅Si₂I, Si₃I₈, HSi₂I₅, H₂ Si₂ 1 ₄, H₃Si₂I₃, H₄Si₂I₂,H₅Si₂I, MeSiI₃, Me₂SiI₂, Me₃SiI, MeSi₂I₅, Me₂Si₂I₄, Me₃Si₂I₃, Me₄Si₂I₂,Me₅Si₂I, HMeSiI₂, HMe₂SiI, HMeSi₂I₄, HMe₂Si₂I₃, HMe₃Si₂I₂, HMe₄Si₂I,H₂MeSiI, H₂MeSi₂I₃, H₂Me₂Si₂I₂, H₂Me₃Si₂I, H₃MeSi₂I₂, H₃Me₂Si₂I,H₄MeSi₂I, EtSiI₃, Et₂SiI₂, Et₃SiI, EtSi₂I₅, Et₂Si₂I₄, Et₃Si₂I₃,Et₄Si₂I₂, Et₅Si₂I, HEtSiI₂I₂, HEt₂SiI, HEtSi₂I₄, HEt₂Si₂I₃, HEt₃Si₂I₂,HEt₄Si₂I, H₂EtSiI, H₂EtSi₂I₃, H₂Et₂Si₂I₂, H₂Et₃Si₂I, H₃EtSi₂I₂,H₃Et₂Si₂I, and H₄EtSi₂I.

In some embodiments, a silicon halide precursor comprises one or more ofthe following: EtMeSiI₂, Et₂MeSiI, EtMe₂SiI, EtMeSi₂I₄, Et₂MeSi₂I₃,EtMe₂Si₂I₃, Et₃MeSi₂I₂, Et₂Me₂Si₂I₂, EtMe₃Si₂I₂, Et₄MeSi₂I, Et₃Me₂Si₂I,Et₂Me₃Si₂I, EtMe₄Si₂I, HEtMeSiI, HEtMeSi₂I₃, HEt₂MeSi₂I₂, HEtMe₂Si₂I₂,HEt₃MeSi₂I, HEt₂Me₂Si₂I, HEtMe₃Si₂I, H₂EtMeSi₂I₂, H₂Et₂MeSi₂I,H₂EtMe₂Si₂I, H₃EtMeSi₂I.

In some embodiments, a silicon halide precursor comprises one or more ofthe following: HSiI₃, H₂SiI₂, H₃SiI, H₂Si₂I₄, H₄Si₂I₂, H₅Si₂I, MeSiI₃,Me₂SiI₂, Me₃SiI, Me₂Si₂I₄, Me₄Si₂I₂, HMeSiI₂, H₂Me₂Si₂I₂, EtSiI₃,Et₂SiI₂, Et₃SiI, Et₂Si₂I₄, Et₄Si₂I₂, and HEtSiI₂. In some embodiments asilicon halide precursor comprises two, three, four, five, six, seven,eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen,seventeen, eighteen, nineteen or more compounds selected from HSiI₃,H₂SiI₂, H₃SiI, H₂Si₂I₄, H₄Si₂I₂, H₅Si₂I, MeSiI₃, Me₂SiI₂, Me₃SiI,Me₂Si₂I₄, Me₄Si₂I₂, HMeSiI₂, H₂Me₂Si₂I₂, EtSiI₃, Et₂SiI₂, Et₃SiI,Et₂Si₂I₄, Et₄Si₂I₂, and HEtSiI₂, including any combinations thereof. Incertain embodiments, the silicon halide precursor is H₂SiI₂.

In some embodiments, a silicon halide precursor comprises a threeiodines and one amine or alkylamine ligands bonded to silicon. In someembodiments silicon halide precursor comprises one or more of thefollowing: (SiI₃)NH₂, (SiI₃)NHMe, (SiI₃)NHEt, (SiI₃)NH^(i)Pr,(SiI₃)NH^(t)Bu, (SiI₃)NMe₂, (SiI₃)NMeEt, (SiI₃)NMe^(i)Pr,(SiI₃)NMe^(t)Bu, (SiI₃)NEt₂, (SiI₃)NEt^(i)Pr, (SiI₃)NEt^(t)Bu,(SiI₃)N^(i)Pr₂, (SiI₃)N^(i)Pr^(t)Bu, and (SiI₃)N^(t)Bu₂. In someembodiments, a silicon halide precursor comprises two, three, four,five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen,fifteen or more compounds selected from (SiI₃)NH₂, (SiI₃)NHMe,(SiI₃)NHEt, (SiI₃)NH^(i)Pr, (SiI₃)NH^(t)Bu, (SiI₃)NMe₂, (SiI₃)NMeEt,(SiI₃)NMe^(i)Pr, (SiI₃)NMe^(t)Bu, (SiI₃)NEt₂, (SiI₃)NEt^(i)Pr,(SiI₃)NEt^(t)Bu, (SiI₃)N^(i)Pr₂, (SiI₃)N^(i)Pr^(t)Bu, (SiI₃)N^(t)Bu₂,and combinations thereof. In some embodiments, a silicon halideprecursor comprises two iodines and two amine or alkylamine ligandsbonded to silicon. In some embodiments, silicon halide precursorcomprises one or more of the following: (SiI₂)(NH₂)₂, (SiI₂)(NHMe)₂,(SiI₂)(NHEt)₂, (SiI₂)(NH^(i)Pr)₂, (SiI₂)(NH^(t)Bu)₂, (SiI₂)(NMe₂)₂,(SiI₂)(NMeEt)₂, (SiI₂)(NMe^(i)Pr)₂, (SiI2)(NMe^(t)Bu)₂, (SiI₂)(NEt₂)₂,(SiI₂)(NEt^(i)Pr)₂, (SiI₂)(NEt^(t)Bu)₂, (SiI₂)(N^(i)Pr₂)₂,(SiI₂)(N^(i)Pr^(t)Bu)₂, and (SiI₂)(N^(t)Bu)₂. In some embodiments, asilicon halide precursor comprises two, three, four, five, six, seven,eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen or morecompounds selected from (SiI₂)(NH₂)₂, (SiI₂)(NHMe)₂, (SiI₂)(NHEt)₂,(SiI₂)(NH^(i)Pr)₂, (SiI₂)(NH^(t)Bu)₂, (SiI₂)(NMe₂)₂, (SiI₂)(NMeEt)₂,(SiI₂)(NMe^(i)Pr)₂, (SiI2)(NMe^(t)Bu)₂, (SiI₂)(NEt₂)₂,(SiI₂)(NEt^(i)Pr)₂, (SiI₂)(NEt^(t)Bu)₂, (SiI₂)(N^(i)Pr₂)₂,(SiI₂)(N^(i)Pr^(t)Bu)₂, (SiI₂)(N^(t)Bu)₂, and combinations thereof.

In some embodiments, a silicon halide precursor comprises two iodines,one hydrogen and one amine or alkylamine ligand bonded to silicon. Insome embodiments silicon halide precursor comprises one or more of thefollowing: (SiI₂H)NH₂, (SiI₂H)NHMe, (SiI₂H)NHEt, (SiI₂H)NH^(i)Pr,(SiI₂H)NH^(t)Bu, (SiI₂H)NMe₂, (SiI₂H)NMeEt, (SiI₂H)NMe^(i)Pr,(SiI₂H)NMe^(t)Bu, (SiI₂H)NEt₂, (SiI₂H)NEt^(i)Pr, (SiI₂H)NEt^(t)Bu,(SiI₂H)N^(i)Pr₂, (SiI₂H)N^(i)P_(r) ^(t)Bu, and (SiI₂H)N^(t)Bu₂. In someembodiments a silicon halide precursor comprises two, three, four, five,six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen,fifteen or more compounds selected from (SiI₂H)NH₂, (SiI₂H)NHMe,(SiI₂H)NHEt, (SiI₂H)NH^(i)Pr, (SiI₂H)NH^(t)Bu, (SiI₂H)NMe₂,(SiI₂H)NMeEt, (SiI₂H)NMe^(i)Pr, (SiI₂H)NMe^(t)Bu, (SiI₂H)NEt₂,(SiI₂H)NEt^(i)Pr, (SiI₂H)NEt^(t)Bu, (SiI₂H)N^(i)Pr₂,(SiI₂H)N^(i)Pr^(t)Bu, (SiI₂H)N^(t)Bu₂, and combinations thereof.

In some embodiments, a silicon halide precursor comprises one iodine,one hydrogen and two amine or alkylamine ligand bonded to silicon. Insome embodiments, silicon halide precursor comprises one or more of thefollowing: (SiIH)(NH₂)₂, (SiIH)(NHMe)₂, (SiIH)(NHEt)₂,(SiIH)(NH^(i)Pr)₂, (SiIH)(NH^(t)Bu)₂, (SiIH)(NMe₂)₂, (SiIH)(NMeEt)₂,(SiIH)(NMe^(i)Pr)₂, (SiIH)(NMe^(t)Bu)₂, (SiIH)(NEt₂)₂,(SiIH)(NEt^(i)Pr)₂, (SiIH)(NEt^(t)Bu)₂, (SiIH)(N^(i)Pr₂)₂,(SiIH)(N^(i)Pr^(t)Bu)₂, and (SiIH)(N^(t)Bu)₂. In some embodiments, asilicon halide precursor comprises two, three, four, five, six, seven,eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen or morecompounds selected from (SiIH)(NH₂)₂, (SiIH)(NHMe)₂, (SiIH)(NHEt)₂,(SiIH)(NH^(i)Pr)₂, (SiIH)(NH^(t)Bu)₂, (SiIH)(NMe₂)₂, (SiIH)(NMeEt)₂,(SiIH)(NMe^(i)Pr)₂, (SiIH)(NMe^(t)Bu)₂, (SiIH)(NEt₂)₂,(SiIH)(NEt^(i)Pr)₂, (SiIH)(NEt^(t)Bu)₂, (SiIH)(N^(i)Pr₂)₂,(SiIH)(N^(i)Pr^(t)Bu)₂, and (SiIH)(N^(t)Bu)₂, and combinations thereof.

In some embodiments, a silicon halide precursor comprises one iodine,two hydrogens and one amine or alkylamine ligand bonded to silicon. Insome embodiments silicon halide precursor comprises one or more of thefollowing: (SiIH₂)NH₂, (SiIH₂)NHMe, (SiIH₂)NHEt, (SiIH₂)NH^(i)Pr,(SiIH₂)NH^(t)Bu, (SiIH₂)NMe₂, (SiIH₂)NMeEt, (SiIH₂)NMe^(i)Pr,(SiIH₂)NMe^(t)Bu, (SiIH₂)NEt₂, (SiIH₂)NEt^(i)Pr, (SiIH₂)NEt^(t)Bu,(SiIH₂)N^(i)Pr₂, (SiIH2)N^(i)Pr^(t)Bu, and (SiIH₂)N^(t)Bu₂. In someembodiments a silicon halide precursor comprises two, three, four, five,six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen,fifteen or more compounds selected from (SiIH₂)NH₂, (SiIH₂)NHMe,(SiIH₂)NHEt, (SiIH₂)NH^(i)Pr, (SiIH₂)NH^(t)Bu, (SiIH₂)NMe₂,(SiIH₂)NMeEt, (SiIH₂)NMe^(i)Pr, (SiIH₂)NMe^(t)Bu, (SiIH₂)NEt₂,(SiIH₂)NEt^(i)Pr, (SiIH₂)NEt^(t)Bu, (SiIH₂)N^(i)Pr₂,(SiIH₂)N^(i)Pr^(t)Bu, (SiIH₂)N^(t)Bu₂, and combinations thereof.

In some embodiments, a silicon halide precursor comprises one iodine andthree amine or alkylamine ligands bonded to silicon. In someembodiments, silicon halide precursor comprises one or more of thefollowing: (SiI)(NH₂)₃, (SiI)(NHMe)₃, (SiI)(NHEt)₃, (SiI)(NH^(i)Pr)₃,(SiI)(NH^(t)Bu)₃, (SiI)(NMe₂)₃, (SiI)(NMeEt)₃, (SiI)(NMe^(i)Pr)₃,(SiI)(NMe^(t)Bu)₃, (SiI)(NEt₂)₃, (SiI)(NEt^(i)Pr)₃, (SiI)(NEt^(t)Bu)₃,(SiI)(N^(i)Pr₂)₃, (SiI)(N^(i)Pr^(t)Bu)₃, and (SiI)(N^(t)Bu)₃. In someembodiments a silicon halide precursor comprises two, three, four, five,six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen,fifteen or more compounds selected from (SiI)(NH₂)₃, (SiI)(NHMe)₃,(SiI)(NHEt)₃, (SiI)(NH^(i)Pr)₃, (SiI)(NH^(t)Bu)₃, (SiI)(NMe₂)₃,(SiI)(NMeEt)₃, (SiI)(NMe^(i)Pr)₃, (SiI)(NMe^(t)Bu)₃, (SiI)(NEt₂)₃,(SiI)(NEt^(i)Pr)₃, (SiI)(NEt^(t)Bu)₃, (SiI)(N^(i)Pr₂)₃,(SiI)(N^(i)Pr^(t)Bu)₃, (SiI)(N^(t)Bu)₃, and combinations thereof.

In certain embodiments, a silicon halide precursor comprises twoiodines, hydrogen and one amine or alkylamine ligand or two iodines andtwo alkylamine ligands bonded to silicon and wherein amine or alkylamineligands are selected from amine NH₂—, methylamine MeNH—, dimethylamineMe₂N—, ethylmethylamine EtMeN—, ethylamine EtNH—, and diethylamineEt₂N—. In some embodiments silicon halide precursor comprises one ormore of the following: (SiI₂H)NH₂, (SiI₂H)NHMe, (SiI₂H)NHEt,(SiI₂H)NMe₂, (SiI₂H)NMeEt, (SiI₂H)NEt₂, (SiI₂)(NH₂)₂, (SiI₂)(NHMe)₂,(SiI₂)(NHEt)₂, (SiI₂)(NMe₂)₂, (SiI₂)(NMeEt)₂, and (SiI₂)(NEt₂)₂. In someembodiments a silicon halide precursor comprises two, three, four, five,six, seven, eight, nine, ten, eleven, twelve or more compounds selectedfrom (SiI₂H)NH₂, (SiI₂H)NHMe, (SiI₂H)NHEt, (SiI₂H)NMe₂, (SiI₂H)NMeEt,(SiI₂H)NEt₂, (SiI₂)(NH₂)₂, (SiI₂)(NHMe)₂, (SiI₂)(NHEt)₂, (SiI₂)(NMe₂)₂,(SiI₂)(NMeEt)₂, (SiI₂)(NEt₂)₂, and combinations thereof.

Other Types of Si-Precursors Containing I or Br

A number of suitable silicon halide precursors containing nitrogen, suchas iodine or bromine substituted silazanes, or sulphur, may be used inthe presently disclosed thermal and plasma ALD processes. In someembodiments silicon halide precursors containing nitrogen, such asiodine or bromine substituted silazanes, may be used in the presentlydisclosed thermal and plasma ALD processes in which a film with desiredquality is to be deposited, for example at least one of the desired WER,WERR, pattern loading effect or/and step coverage features describedbelow.

At least some of the suitable iodine or bromine substituted siliconhalide precursors may have the following general formula:

H_(2n+2−y−z−w)Si_(n)(EH)_(n−1)X_(y)A_(z)R_(w)  (25)

wherein, n=2-10, y=1 or more (and up to 2n+2−z−w), z=0 or more (and upto 2n+2−y−w), w=0 or more (and up to 2n+2−y−z), X is I or Br, E is N orS, preferably N, A is a halogen other than X, R is an organic ligand andcan be independently selected from the group consisting of alkoxides,alkylsilyls, alkyl, substituted alkyl, alkylamines and unsaturatedhydrocarbon; preferably n=2-5 and more preferably n=2-3 and mostpreferably 1-2. Preferably R is a C₁-C₃ alkyl ligand, such as methyl,ethyl, n-propyl or isopropyl.

At least some of the suitable iodine or bromine substituted silazaneprecursors may have the following general formula:

H_(2n+2−y−z−w)Si_(n)(NH)_(n−1)X_(y)A_(z)R_(w)  (26)

wherein, n=2-10, y=1 or more (and up to 2n+2−z−w), z=0 or more (and upto 2n+2−y−w), w=0 or more (and up to 2n+2−y−z), X is I or Br, A is ahalogen other than X, R is an organic ligand and can be independentlyselected from the group consisting of alkoxides, alkylsilyls, alkyl,substituted alkyl, alkylamines and unsaturated hydrocarbon; preferablyn=2-5 and more preferably n=2-3 and most preferably 2. Preferably R is aC₁-C₃ alkyl ligand, such as methyl, ethyl, n-propyl or isopropyl.

In some embodiments, the silicon halide precursor comprises Si-compound,such as heterocyclic Si compound, which comprises I or Br. Such cyclicprecursors may comprise the following substructure:

—Si-E-Si—  (27)

wherein E is N or S, preferably N.

In some embodiments the silicon halide precursor comprises substructureaccording to formula (27) and example of this kind of compounds is forexample, iodine or bromine substituted cyclosilazanes, such iodine orbromine substituted cyclotrisilazane.

In some embodiments, the silicon halide precursor comprises Si-compound,such as silylamine based compound, which comprises I or Br. Suchsilylamine based Si-precursors may have the following general formula:

(H_(3-y-z-w)X_(y)A_(z)R_(w)Si)₃—N  (28)

wherein, y=1 or more (and up to 3−z−w), z=0 or more (and up to 3−y−w),w=0 or more (and up to 3−y−z), X is I or Br, A is a halogen other thanX, R is an organic ligand and can be independently selected from thegroup consisting of alkoxides, alkylsilyls, alkyl, substituted alkyl,alkylamines and unsaturated hydrocarbon. Preferably R is a C₁-C₃ alkylligand, such as methyl, ethyl, n-propyl or isopropyl. Each of the threeH_(3-y-z-w)X_(y)A_(z)R_(w)Si ligands can be independently selected fromeach other.

Other Types of Si Containing Precursors

Silicon halide precursors comprising chloride or fluoride may also beused. In such precursor the halogens such as iodide and bromide asdescribed in the above general formula's may be replaced by chloride(Cl) or fluoride (F).

O Precursors

A number of suitable reactants may be used in the presently disclosedprocesses. These reactant may be used in plasma ALD or plasma CVDprocesses thereby a layer with a desired quality (at least one of thedesired WER, WERR, pattern loading effect or/and step coverage featuresdescribed below) is deposited.

According to some embodiments, the reactant in a thermal ALD process maybe O₂, H₂O, H₂O₂, or any number of other suitable oxygen compoundshaving a O—H bond.

Silicon Dioxide Film Characteristics

The first silicon dioxide thin films deposited according to some of theembodiments discussed herein (irrespective of whether the silicon halideprecursor contained bromine or iodine) may achieve impurity levels orconcentrations below about 3%, preferably below about 1%, morepreferably below about 0.5%, and most preferably below about 0.1%. Insome thin films, the total impurity level excluding hydrogen may bebelow about 5%, preferably below about 2%, more preferably below about1%, and most preferably below about 0.2%. And in some thin films,hydrogen levels may be below about 30%, preferably below about 20%, morepreferably below about 15%, and most preferably below about 10%.

In some embodiments, the deposited silicon dioxide films do not comprisean appreciable amount of carbon. However, in some embodiments a silicondioxide film comprising carbon is deposited. For example, in someembodiments an ALD reaction is carried out using a silicon halideprecursor comprising carbon and a thin silicon dioxide film comprisingcarbon is deposited. In some embodiments a silicon dioxide filmcomprising carbon is deposited using a precursor comprising an alkylgroup or other carbon-containing ligand. In some embodiments a siliconhalide precursor of one of formulas (9)-(28) and comprising an alkylgroup is used in a PEALD or thermal ALD process, as described above, todeposit a silicon dioxide film comprising carbon. Different alkylgroups, such as Me or Et, or other carbon-containing ligands may producedifferent carbon concentrations in the films because of differentreaction mechanisms. Thus, different precursors can be selected toproduce different carbon concentration in deposited silicon dioxidefilms. In some embodiments the thin silicon dioxide film comprisingcarbon may be used, for example, as a low-k spacer. In some embodimentsthe thin films do not comprise argon.

According to some embodiments, the silicon dioxide thin films mayexhibit step coverage and pattern loading effects of greater than about50%, preferably greater than about 80%, more preferably greater thanabout 90%, and most preferably greater than about 95%. In some casesstep coverage and pattern loading effects can be greater than about 98%and in some case about 100% (within the accuracy of the measurement toolor method). These values can be achieved in aspect ratios of more than2, preferably in aspect ratios more than 3, more preferably in aspectratios more than 6 and most preferably in aspect ratios more than 11.

As used herein, “pattern loading effect” is used in accordance with itsordinary meaning in this field. While pattern loading effects may beseen with respect to impurity content, density, electrical propertiesand etch rate, unless indicated otherwise the term pattern loadingeffect when used herein refers to the variation in film thickness in anarea of the substrate where structures are present. Thus, the patternloading effect can be given as the film thickness in the sidewall orbottom of a feature inside a three-dimensional structure relative to thefilm thickness on the sidewall or bottom of the three-dimensionalstructure/feature facing the open field. As used herein, a 100% patternloading effect (or a ratio of 1) would represent about a completelyuniform film property throughout the substrate regardless of featuresi.e. in other words there is no pattern loading effect (variance in aparticular film property, such as thickness, in features vs. openfield).

In some embodiments, silicon dioxide films are deposited to athicknesses of from about 1 nm to about 50 nm, preferably from about 3nm to about 30 nm, more preferably from about 4 nm to about 15 nm. Thesethicknesses can be achieved in feature sizes (width) below about 100 nm,preferably about 50 nm, more preferably below about 30 nm, mostpreferably below about 20 nm, and in some cases below about 15 nm.According to some embodiments, a silicon dioxide film is deposited on athree-dimensional structure and the thickness at a sidewall may bearound 10 nm.

It has been found that in using the silicon dioxide thin films of thepresent disclosure, thickness differences between top and side may notbe as critical for some applications, due to the improved film qualityand etch characteristics. Nevertheless, in some embodiments, thethickness gradient along the sidewall may be very important tosubsequent applications or processes.

Example PECVD

A silicon dioxide thin layer was deposited at 550° C. with a plasmapower of 600 W at a pressure of about 2.6 torr in a plasma enhancedchemical vapor deposition reactor. The O₂ flow is 4 splm, the Ar flow is2.8 splm and a seal He flow of 0.28 splm is applied. H2SiI2 is used asthe silicon halide precursor. Si precursor was supplied continuouslyduring plasma step.

FIG. 2a discloses a wafer map as the CVD layer is deposited. Thereflective index RI=1.49. FIG. 2b discloses the wafer map of the sameCVD layer after 10 min. in 0.5% HF etch. The wet etch rate WERR=2.8 andthe DR (Deposition rate)˜100 nm/min. The wet etch rate Werr is definedas the wet etch rate of the layer divided by the wet etch rate of thethermal oxide.

FIG. 3a discloses a wafer map with a CVD layer which is deposited withthe same process as above except that the temperature is lowered to 400°C., which makes the process compatible with the back end of line (BEOL)processes. FIG. 3b discloses the wafer map of the same CVD layer after 5min. in 0.5% HF etch. The WERR=4.1 and the DR˜800 nm/min. Allexperiments were run with an XP8 available from ASM Japan K.K (Tokyo,Japan).

Example PEALD

A silicon dioxide thin layer was deposited at 550° C. with a plasmapower of 600 W at a pressure of about 2.6 torr in a plasma enhancedatomic layer vapor deposition reactor. The O2 flow was 4 splm, the Arflow was 2.8 splm and a seal He flow of 0.28 splm was applied. H₂SiI₂ isused as the silicon halide precursor. The pulse scheme was 0.3 sec/0.8sec/3 sec/0.1 sec (feed/purge/RF_on/purge). The O is providedcontinuously during the process. The silicon dioxide layer had thefollowing properties:

FIG. 4a discloses a wafer map as the ALD layer is deposited. Thereflective index RI=1.49. FIG. 4b discloses the wafer map of the sameALD layer after 3 min. in 0.5% HF etch. The wet etch rate WERR=1.1 ,this number is remarkably low because typical high quality PEALD silicondioxide layers achieve a WERR 2, at best 1.4.

FIG. 5a discloses a wafer map with an ALD layer which is deposited withthe same process as above except that the temperature is lowered to 400°C., which makes the process compatible with the back end of line (BEOL)processes. FIG. 5b discloses the wafer map of the same ALD layer after 2min. in 0.5% HF etch. The WERR=1.1 revealing the very high quality ofSiO2 achieved. Again the experiment have been done with a XP8.

Plasma Treatment

As described herein, plasma treatment steps may be used in formation ofa variety of materials to enhance film properties. In particular,utilization of a plasma densification step, for example using an argonplasma, may enhance the properties of dioxide films, such as silicondioxide films. In some embodiments, a process for forming silicondioxide films comprises depositing the silicon dioxide and treating thedeposited silicon dioxide with a plasma treatment. In some embodiments,the silicon dioxide is deposited by a thermal ALD process, andsubsequently subjected to a plasma treatment. For example, silicondioxide may be deposited by a thermal ALD process comprising a pluralityof deposition cycles comprising a first phase in which a substrate iscontacted with a silicon halide precursor such that silicon species areadsorbed onto a surface of the substrate, and a second phase in whichthe silicon species adsorbed onto the substrate surface are contactedwith an oxygen precursor. As discussed herein, the silicon oxidedeposited by the thermal ALD process may be subject to a plasmatreatment, for example after each deposition cycle, at intervals duringthe deposition process or following completion of the silicon oxidedeposition process. Unwanted oxidation due to O plasma exposure is wellknown issue. However SiO2 plasma processes films have typically muchhigher quality. It is expected that combining thermal SiO2 depositionand plasma treatment both low oxidation and high quality SiO2 films canbe achieved. In some embodiments, silicon oxide is deposited by a PEALDprocess. In some embodiments, a PEALD deposition process comprises afirst phase and a second phase. For example, a first phase of a siliconoxide PEALD process may comprise contacting a target substrate with asilicon precursor such that silicon species are adsorbed onto a surfaceof the target substrate and a second phase of the silicon oxide PEALDprocess may comprise contacting the silicon species adsorbed onto thesurface of the target substrate with a plasma comprising oxygen in orderto form silicon oxide. In this part of the deposition process, theplasma may comprise argon ions. For example, a PEALD silicon dioxidedeposition cycle may include contacting the target substrate with asilicon precursor, such as those described herein, and an activatedoxygen precursor, for example a plasma of oxygen and argon gas. Thetarget substrate may be exposed to activated argon containing species(e.g., Ar⁺ and/or Ar2⁺ ions) in this step, which may, for example,densify the layer. In some embodiments, subsequent to deposition ofsilicon oxide by PEALD, a second plasma treatment step is carried out.The second plasma treatment step may be carried out after each PEALDcycle, at intervals during silicon oxide deposition, or after the PEALDsilicon oxide deposition process is complete. The second plasmatreatment step may be an Ar plasma treatment step. The second plasmastep may, for example, lead to densification of the deposited siliconoxide film or otherwise improve film properties. Thus, the second Arplasma treatment step may also be referred to as a densification step.The plasma power and/or duration may be greater in the densificationstep (second Ar plasma treatment step) than in the first oxygen reactantstep, as discussed in more detail below. Therefore a low power may beprovided during the O plasma step (to minimize substrate oxidation) anda high power during the Ar plasma step to achieve high quality SiO. Thedensification step may be carried out after every cycle of a PEALDprocess, or after various intervals of the PEALD deposition process, asdiscussed in more detail below.

Thus, in some embodiments, one or more silicon dioxide film depositioncycles can be followed by an argon plasma treatment. Utilizing the argonplasma treatment may facilitate formation of silicon dioxide filmshaving certain desired characteristics. Without being limited by anyparticular theory or mode of operation, application of an argon plasmatreatment may increase a density of the silicon dioxide film formed bythe silicon dioxide film deposition cycles. In some embodiments,application of an argon plasma treatment can facilitate formation of asilicon dioxide film which demonstrates increased resistance to wet etch(e.g., as compared to silicon dioxide films formed without an argonplasma treatment, in which the top layer may be easily oxidized anddemonstrate similar WERR as that of thermal silicon oxide). In someembodiments, application of an argon plasma treatment can facilitateformation of a silicon dioxide film having increased etch rateuniformity of horizontal surfaces relative to vertical surfaces on 3-Dfeatures, decreased wet etch rate (WER), and/or decreased wet etch rateratio (WERR) relative to thermal oxide (TOX).

In some embodiments, utilizing an argon plasma treatment may facilitateformation of silicon dioxide films useful in applications such ashardmasks, sacrificial layers, gate spacers and/or spacer defineddouble/quadruple patterning (SDDP/SDQP) in state-of-the-artsemiconductor devices such as FiNFETs and other multigate transistors.

Although embodiments described herein refer to PEALD deposition ofsilicon dioxide films, it will be understood that other depositiontechniques may also be applicable (e.g., thermal ALD, and/or radicalenhanced ALD). Further, the argon plasma treatment may be applied to thedeposition of other materials (e.g., metallic materials, dielectricmaterials, and/or other dioxide materials, such as titanium dioxide(TiO2)).

In some embodiments, plasma power in a PEALD process for depositingsilicon dioxide is sufficiently low to reduce or avoid formation of filmdefects and/or delamination. However, the plasma power may be higher inthe argon plasma treatment. Thus, in some embodiments, a plasma powerused in an argon plasma treatment is greater than or equal to that usedin a PEALD process for depositing silicon dioxide (e.g., an oxygenprecursor step of the PEALD process). For example, in a PEALD cycle forforming silicon oxide, a plasma may be formed with a gas comprisingoxygen and argon using a reduced plasma power. In some embodiments, aplasma power applied during the argon plasma treatment is up to about900% that of a plasma power applied during a PEALD process for formingsilicon oxide where (e.g., during an oxygen precursor step of the PEALDprocess). In some embodiments, a plasma power for the oxygen plasmatreatment is preferably up to about 400% that of the plasma power usedin the oxygen precursor step, more preferably about 100% to about 250%that of the plasma power used in the oxygen precursor step, and mostpreferably about 100% to about 200% that of the plasma power used in theoxygen precursor step.

In some embodiments, a plasma power used in an argon plasma treatment isless than that used in an oxygen precursor step. For example, a plasmapower used in the oxygen plasma treatment can be between about 50% and100% of a plasma power used in the oxygen precursor step.

Plasma power used in a PEALD silicon dioxide deposition process candepend on various factors, including a geometry of structures and/ormaterial of the target substrate on which the silicon dioxide isdeposited. As described herein, plasma power used in a cycle of PEALDsilicon dioxide deposition may be about 50 Watts (W) to about 600 W(e.g., in a reaction chamber configured for processing a 300 millimeter(mm) wafer substrate), including for example from about 100 W to about300 W, and from about 150 W to about 250 W. As described herein, aplasma power applied during an argon plasma treatment may be greaterthan or equal to a plasma power applied during the precursor step,including for example, about 100 W to about 1000 W, preferably about 125W to about 600 W, more preferably about 150 W to about 300 W. In someembodiments, a power density of a plasma applied during an oxygen plasmatreatment (e.g., in a reaction chamber configured for processing a 300millimeter (mm) wafer substrate) can be about 0.07 Watts per cubiccentimeter (W/cm³) to about 70 W/cm³, preferably about 0.08 W/cm³ toabout 0.4 W/cm³W, and more preferably about 0.1 W/cm³ about 0.2 W/cm³.For ignition of the plasma other gases than argon and hydrogen can beadded to the plasma.

A duration of the argon plasma treatment can be selected to obtaindesired results. In some embodiments the duration is based, in part, ona thickness of the silicon dioxide film being treated. For example, ashorter argon plasma treatment can be used in the argon plasma treatmentapplied after each PEALD cycle, while a longer argon plasma treatmentcan be used when the argon plasma treatment is applied less frequently.

As described herein, a silicon dioxide formation process may include aplurality of deposition cycles for depositing the silicon dioxide filmand one or more argon plasma treatments steps, where each depositioncycle can include a silicon precursor step followed by an oxygenprecursor step. In some embodiments, a cycle including a plurality ofdeposition cycles (e.g., a deposition cycle including a siliconprecursor step followed by oxygen precursor step) and one or more argonplasma treatment steps, can be repeated a number of times. In someembodiments, a plurality of deposition cycles can be repeated to achievea desired silicon dioxide film thickness, which then can be followed byone or more Ar plasma treatment steps.

In some embodiments, an Argon plasma treatment of a silicon dioxidedeposition process can have a total duration of about 1% to about 100%the total duration in which activated hydrogen containing species areprovided in the oxygen precursor step, preferably about 5% to about 75%that of the total duration in which activated hydrogen containingspecies are provided of in the oxygen precursor step, and morepreferably about 10% to about 50%.

The frequency with which the target substrate is exposed to the Arplasma treatment can be selected to achieve desired final filmcharacteristics. For example, one or more Ar plasma treatments canfollow a number of repetitions of cycles in which the target substrateis exposed to one or more silicon halide precursors followed by oxygenprecursors for silicon dioxide film growth. In some embodiments, cyclesof exposing the target substrate to one or more silicon precursorsfollowed by oxygen precursors can be repeated twenty-five times, beforeeach Ar plasma treatment. For example, an Ar plasma treatment can followevery repetition of twenty-five cycles of exposing the target substrateto one or more silicon precursors followed by oxygen precursors. In someembodiments, an Ar plasma treatment can follow every repetition of fiftycycles of exposing the target substrate to one or more siliconprecursors followed by oxygen precursors. In some embodiments, an Arplasma treatment can follow every repetition of one hundred cycles ofexposing the target substrate to one or more silicon precursors followedby oxygen precursors.

Without being limited by any particular theory or mode of operation, aplasma Ar treatment can be applied for densification of the silicondioxide film, such as through ion bombardment of the silicon dioxidefilm. In some embodiments, a frequency at which an Ar plasma treatmentcan be applied during a silicon dioxide film formation process can beafter about at least every 100^(th) cycle of silicon dioxide filmdeposition, preferably after at least every 50^(th) and most preferablyafter at least every 25^(th).

In some embodiments, a thickness of the silicon dioxide film formed isless than about 3 nm, preferably less than about 2 nm, and morepreferably less than about 1 nm, for example such that an etch rate ofmost or all of the silicon dioxide film thickness can be improved afterbeing treated by an oxygen plasma treatment. In some embodiments, asilicon dioxide film thickness can be less than about 0.5 nm.

In some embodiments, a number of cycles between Ar plasma treatments canbe selected based on a trade-off between silicon dioxide film etchproperties and throughput. For example, while good etch properties canbe achieved with an argon plasma treatment applied after everydeposition cycle but will significantly reduce throughput. Thus, theskilled artisan can adjust the treatment ratio in order to form suitablefilms in the most efficient manner.

In some embodiments, process for depositing a silicon oxide layerincludes a multi-step plasma exposure. For example, an hydrogen H plasmacan be provided to perform a H plasma treatment. The method may besimilar as the argon plasma as described above with the argon replacedwith hydrogen. This time it is not high quality/densification that isaccomplished. Hydrogen plasma treatment has two effect: the first effectis to provide more reactive sites (—OH surface group) to increase thegrowth per cycle (GPC) and a second effect of voluntarily creating ahigh WER to the layer by H incorporation (less dense films). H2 and O2cannot be mixed in the reactor, so purge steps are necessary betweenboth gases. H2 plasma is typically, but not necessarily generated withAr, the Ar/H ration should be <10 preferably <4. High power for the H2treatment will amplify the two effects described above. Higherconformality can also be achieved due to the isotropic nature of Hplasma comprising large amount of radical species. Multiple plasma stepmay be added/combine of Ar and H plasma step in any ratio to achievedesired film properties: high conformality, low or high WERR.

It will be understood by those of skill in the art that numerous andvarious modifications can be made without departing from the spirit ofthe present invention. The described features, structures,characteristics and precursors can be combined in any suitable manner.Therefore, it should be clearly understood that the forms of the presentinvention are illustrative only and are not intended to limit the scopeof the present invention. All modifications and changes are intended tofall within the scope of the invention, as defined by the appendedclaims.

It is to be understood that the configurations and/or approachesdescribed herein are exemplary in nature, and that these specificembodiments or examples are not to be considered in a limiting sense,because numerous variations are possible. The specific routines ormethods described herein may represent one or more of any number ofprocessing strategies. Thus, the various acts illustrated may beperformed in the sequence illustrated, in other sequences, or omitted insome cases.

1. A method of providing a structure by depositing a layer on asubstrate in a reactor, the method comprising: introducing a siliconhalide precursor comprising iodine or bromine in the reactor;introducing a reactant gas comprising oxygen in the reactor; and,providing an energy source to create a plasma from the reactant gas sothat the oxygen reacts with the silicon halide precursor comprisingiodine or bromine into the layer comprising silicon dioxide.
 2. Themethod according to claim 1, wherein a carrier gas is used to introducethe silicon halide precursor in the reactor.
 3. The method according toclaim 1, wherein the reactant gas comprises substantially no nitrogen.4. The method according to claim 2, wherein the carrier gas comprisesargon.
 5. The method according to claim 1, wherein the reactant gascomprises argon.
 6. The method according to claim 1, wherein atemperature of within a reaction chamber of the reactor is between 25 to700° C.
 7. The method according to claim 1, wherein introducing asilicon halide precursor in the reactor comprises adsorbing the siliconhalide precursor to a surface of the substrate.
 8. The method accordingto claim 1, wherein the method is a plasma enhanced atomic layerdeposition method and the deposition method comprises removing excesssilicon halide precursor and reaction byproducts from the reactor afterintroducing the silicon halide precursor; and, after providing an energysource to create a plasma from the reactant gas.
 9. The method accordingto claim 1, wherein the deposition method also comprises after theplasma is created contacting an adsorbed silicon halide precursor withreactant species of the plasma.
 10. The method according to claim 3,wherein substantially no nitrogen is less than 5000 ppm nitrogen. 11.The method according to claim 1, wherein the method is a plasma enhancedchemical vapor deposition method.
 12. The method of claim 1, wherein thesilicon oxide layer is deposited during formation of a semiconductordevice.
 13. The method according to claim 1, wherein the silicon halideprecursor has a general formula: (1) H_(2n+2−y−)zSi_(n)XyAz, wherein,n=1-10, y=1 or more and up to 2n+2−z, z=0 or more and up to 2n+2−y, X isI or Br, and A is a halogen other than X; or (2)H_(2n+2−y−z)Si_(n)X_(y)A_(z), wherein the formula (2) compound is cycliccompound, n=3-10, y=1 or more and up to 2n−z, z=0 or more and up to2n−y, X is I or Br, and A is a halogen other than X; and wherein thesilicon halide comprises at least one hydrogen.
 14. The method accordingto claim 1, wherein a pressure within a reaction chamber of the reactoris between 0.08 to 40 Torr.
 15. The method according to claim 1, whereinthe plasma is created with an energy source having a power between 50and 1500 Watt.
 16. The method according to claim 1, wherein the oxygenin the reactant gas is provided with a flow of 0.1 to 10 slm.
 17. Themethod according to claim 2, wherein the carrier gas is provided with aflow of 0.5 to 8 slm.
 18. The method according to claim 1, wherein argonin the reactant gas is provided with a flow of 0.1 to 10 slm in thereactor.
 19. The method according to claim 1, comprising applyingadditional argon plasma treatment.
 20. The method according to claim 1,comprising applying additional hydrogen plasma treatment.
 21. The methodaccording to claim 1, comprising multiple hydrogen and argon plasmatreatment.
 22. A method of providing a structure by depositing a layeron a substrate, the method comprising: providing a silicon halideprecursor comprising iodine or bromine in the reactor; providing areactant gas comprising oxygen in the reactor; providing an energysource to create a plasma from the reactant gas so that the reactantreacts with the silicon halide precursor comprising iodine or bromineuntil the layer comprising silicon dioxide is formed.